1. Field of the Invention
The present invention relates to an image forming apparatus, such as a printer, a copying machine, or a facsimile machine.
2. Description of the Related Art
Known image forming apparatuses include those wherein four developing agent cartridges which contain developing agents of the four colors yellow, magenta, cyan, and black, respectively, are attached to a developing device unit which has four developing devices rotatably disposed, to thereby develop color images.
Such an image forming apparatus has a problem that an operator may touch a developing roller exposed out of a developing device when attaching/detaching a cartridge containing developing agent, with the result that his hand, or the like, is stained with the developing agent. To this end, there has been known a technique to cover a developing roller in the developing device with a shutter during attachment/detachment of a cartridge which is provided with a developing device and in which developing agent is contained, thereby preventing an operator's hand, or the like, from touching the developing roller (see JP-A-11-149211).